Modern ICs have helped to integrated electronic circuitry to decrease size and cost. As a consequence, modern ICs can form complex circuitry and systems. For example, virtually all of the functionality of a system may be realized using one or a handful of ICs.
The result has been a growing trend to produce circuitry and systems with increased reliability, flexibility, and functionality. Such circuitry and systems may receive and operate on both analog and digital signals, and may provide analog and digital signals. Consequently, such circuitry and systems may include both analog and digital circuits that interface to one another.